There is a clinical need for biocompatible and biodegradable structural matrices that facilitate tissue infiltration to repair/regenerate diseased or damaged tissue. In general, the clinical approaches to repair damaged or diseased musculoskeletal tissue, such as bone, cartilage, or muscle, do not substantially restore the original function of the tissue. Prosthetic joints/devices often have been used to treat such defects with mixed outcomes attributed to loosening, limited durability, and loss of functional tissue surrounding the defect. Thus, there remains a strong need for alternative approaches for tissue repair/regeneration that avoid the common problems associated with current clinical approaches.
The recent emergence of tissue engineering may offer alternative approaches to repair and regenerate damaged/diseased tissue. Tissue engineering strategies have explored the use of biomaterials in combination with cells and/or growth factors to develop biological substitutes that ultimately can restore or improve tissue function. The use of colonizable and remodelable scaffolding materials has been studied extensively as tissue templates, conduits, barriers, and reservoirs. In particular, synthetic and natural materials in the form of foams, sponges, gels, hydrogels, textiles, and nonwovens have been used in vitro and in vivo to reconstruct/regenerate biological tissue, as well as deliver chemotactic agents for inducing tissue growth.
Regardless of the composition of the scaffold and the targeted tissue, the template must possess some fundamental characteristics. The scaffold must be biocompatible, possess sufficient mechanical properties to resist crumbling at the time of surgery, highly porous to allow cell invasion, or growth, easily sterilized, able to be remodeled by invading tissue, and degradable as the new tissue is being formed. Furthermore, the scaffold may be fixed to the surrounding tissue via mechanical means, fixation devices, or adhesives. So far, conventional materials, alone or in combination, lack one or more of the above criteria.
Accordingly, there is a need for scaffolds that can resolve the potential pitfalls of conventional materials. These scaffolds combine different biocompatible materials to form a superior matrix for musculoskeletal tissue repair without resorting to undesirable and expensive ex vivo cell culturing and/or biological growth factor techniques.